1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Backlight code for via-pmu 4 * 5 * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi. 6 * Copyright (C) 2001-2002 Benjamin Herrenschmidt 7 * Copyright (C) 2006 Michael Hanselmann <linux-kernel@hansmi.ch> 8 * 9 */ 10 11 #include <asm/ptrace.h> 12 #include <linux/adb.h> 13 #include <linux/pmu.h> 14 #include <asm/backlight.h> 15 16 #define MAX_PMU_LEVEL 0xFF 17 18 static const struct backlight_ops pmu_backlight_data; 19 static DEFINE_SPINLOCK(pmu_backlight_lock); 20 static int sleeping, uses_pmu_bl; 21 static u8 bl_curve[FB_BACKLIGHT_LEVELS]; 22 23 static void pmu_backlight_init_curve(u8 off, u8 min, u8 max) 24 { 25 int i, flat, count, range = (max - min); 26 27 bl_curve[0] = off; 28 29 for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat) 30 bl_curve[flat] = min; 31 32 count = FB_BACKLIGHT_LEVELS * 15 / 16; 33 for (i = 0; i < count; ++i) 34 bl_curve[flat + i] = min + (range * (i + 1) / count); 35 } 36 37 static int pmu_backlight_curve_lookup(int value) 38 { 39 int level = (FB_BACKLIGHT_LEVELS - 1); 40 int i, max = 0; 41 42 /* Look for biggest value */ 43 for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) 44 max = max((int)bl_curve[i], max); 45 46 /* Look for nearest value */ 47 for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) { 48 int diff = abs(bl_curve[i] - value); 49 if (diff < max) { 50 max = diff; 51 level = i; 52 } 53 } 54 return level; 55 } 56 57 static int pmu_backlight_get_level_brightness(int level) 58 { 59 int pmulevel; 60 61 /* Get and convert the value */ 62 pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL; 63 if (pmulevel < 0) 64 pmulevel = 0; 65 else if (pmulevel > MAX_PMU_LEVEL) 66 pmulevel = MAX_PMU_LEVEL; 67 68 return pmulevel; 69 } 70 71 static int __pmu_backlight_update_status(struct backlight_device *bd) 72 { 73 struct adb_request req; 74 int level = bd->props.brightness; 75 76 77 if (bd->props.power != FB_BLANK_UNBLANK || 78 bd->props.fb_blank != FB_BLANK_UNBLANK) 79 level = 0; 80 81 if (level > 0) { 82 int pmulevel = pmu_backlight_get_level_brightness(level); 83 84 pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel); 85 pmu_wait_complete(&req); 86 87 pmu_request(&req, NULL, 2, PMU_POWER_CTRL, 88 PMU_POW_BACKLIGHT | PMU_POW_ON); 89 pmu_wait_complete(&req); 90 } else { 91 pmu_request(&req, NULL, 2, PMU_POWER_CTRL, 92 PMU_POW_BACKLIGHT | PMU_POW_OFF); 93 pmu_wait_complete(&req); 94 } 95 96 return 0; 97 } 98 99 static int pmu_backlight_update_status(struct backlight_device *bd) 100 { 101 unsigned long flags; 102 int rc = 0; 103 104 spin_lock_irqsave(&pmu_backlight_lock, flags); 105 /* Don't update brightness when sleeping */ 106 if (!sleeping) 107 rc = __pmu_backlight_update_status(bd); 108 spin_unlock_irqrestore(&pmu_backlight_lock, flags); 109 return rc; 110 } 111 112 113 static const struct backlight_ops pmu_backlight_data = { 114 .update_status = pmu_backlight_update_status, 115 116 }; 117 118 #ifdef CONFIG_PM 119 void pmu_backlight_set_sleep(int sleep) 120 { 121 unsigned long flags; 122 123 spin_lock_irqsave(&pmu_backlight_lock, flags); 124 sleeping = sleep; 125 if (pmac_backlight && uses_pmu_bl) { 126 if (sleep) { 127 struct adb_request req; 128 129 pmu_request(&req, NULL, 2, PMU_POWER_CTRL, 130 PMU_POW_BACKLIGHT | PMU_POW_OFF); 131 pmu_wait_complete(&req); 132 } else 133 __pmu_backlight_update_status(pmac_backlight); 134 } 135 spin_unlock_irqrestore(&pmu_backlight_lock, flags); 136 } 137 #endif /* CONFIG_PM */ 138 139 void __init pmu_backlight_init(void) 140 { 141 struct backlight_properties props; 142 struct backlight_device *bd; 143 char name[10]; 144 int level, autosave; 145 146 /* Special case for the old PowerBook since I can't test on it */ 147 autosave = 148 of_machine_is_compatible("AAPL,3400/2400") || 149 of_machine_is_compatible("AAPL,3500"); 150 151 if (!autosave && 152 !pmac_has_backlight_type("pmu") && 153 !of_machine_is_compatible("AAPL,PowerBook1998") && 154 !of_machine_is_compatible("PowerBook1,1")) 155 return; 156 157 snprintf(name, sizeof(name), "pmubl"); 158 159 memset(&props, 0, sizeof(struct backlight_properties)); 160 props.type = BACKLIGHT_PLATFORM; 161 props.max_brightness = FB_BACKLIGHT_LEVELS - 1; 162 bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data, 163 &props); 164 if (IS_ERR(bd)) { 165 printk(KERN_ERR "PMU Backlight registration failed\n"); 166 return; 167 } 168 uses_pmu_bl = 1; 169 pmu_backlight_init_curve(0x7F, 0x46, 0x0E); 170 171 level = bd->props.max_brightness; 172 173 if (autosave) { 174 /* read autosaved value if available */ 175 struct adb_request req; 176 pmu_request(&req, NULL, 2, 0xd9, 0); 177 pmu_wait_complete(&req); 178 179 level = pmu_backlight_curve_lookup( 180 (req.reply[0] >> 4) * 181 bd->props.max_brightness / 15); 182 } 183 184 bd->props.brightness = level; 185 bd->props.power = FB_BLANK_UNBLANK; 186 backlight_update_status(bd); 187 188 printk(KERN_INFO "PMU Backlight initialized (%s)\n", name); 189 } 190